Profile feature: Agent code
When this profile feature is on, the Agency field is visible in the Personnel box in the Claim Info tab of an open estimate.

Select the menu button to open a dialog where you can choose or add an agency.

Once you select an agency and close the dialog, an agent code populates in the Agency field.
This profile feature is on by default. To deactivate this feature, follow the instructions in How do I find out which profile features are enabled in my profile?